Control means for cleaning machines having solvent recovery system



Jan. 7, 1964 w. H. STEWART CONTROL MEANS F'OR CLEANING MACHINES HAVING SOLVENT RECOVERY SYSTEM A TTONE K5.

Jan. 7, 1964 Filed June 18, 1962 w. H. STEWART 3,116,625 CONTROL MEANS FOR CLEANING MACHINES HAVING SOLVENT RECOVERY SYSTEM 2 Sheets-Sheet 2 United States Patent Olice .ldlhll Patented Jan. 7, 1964 Wil This invention relates generally to control means for cleaning machines employing a solvent recovery system, and refers more particularly to means for maintaining surveillance over and eifecting control of the machine in response to conditions obtaining in the machine during solvent recovery.

One of the principal lields in which my invention finds special value is in the so-called coin operated dry cleaning machine industry. At present the usual practice in such machines is to control the operation cycle of the machine on a straight time program. ln other words, once the machine is set in operation, a program controller establis'ies the length of the cleaning period, that is, when the load is being contacted with the solvent, and the length of the solvent recovery period wherein the solvent is vaporized, withdrawn from the tumbler and condorL e and returned to the reservoir. ln order to prevent injury to users, such machines are locked against access to the interior during the entire operating cycle, the completion oi the cycle actuating the locking mechanism to release same whereby to then permit access.

Because of variance in the size of loads fed to the machines, as well as types of materials which will be cleaned therein, the recovery time allowed must be that which will permit complete recovery from the rnaxirnurn possible loa-:l and most retentive materials. The recovery period in conventional machines therefore ordinarily represents at least 50% ot the total cycle time oi the machine. Efforts have been made to provide in such machines a control for the recovery period based on actual solvent conditions and operable to terminate recovery when the ecovery is complete, independent of tinte. However, for reasons of complexity, cost and op- -rational difficulty, such as plugging of the equipment by sediment and the like, the proposed arrangements have not, to my knowledge, inet with success.

One of the inain objectives oi my invention is to provide control arrangement for the purposes generally set forth above which, because of its structure and manner of combination in the machine, avoids or eliminates the difficulties heretofore set forth, as well as provides ad vantages over presently known equipment of this type.

One aim of the invention is to provide a self-cleaning, nonplugging combined solvent meter and controller of simple construction which is connected into the solvent recovery line from the solvent condense-r, and which serves to monitor the entire ilow from the condenser and to el'lcct changes in a control mechanism in response thereto. ln its preferred embodiment, the meter is so constructed as to provide a chamber' into which the con enscd solvent is directed, the chamber containing a spring loaded diai nragrn which is connected with a needle valve extending into and normally closing an outlet from the chamber. The valve is constructed to vary the size or" the outlet opening as the diaphragm moves in response to pressure changes within the housing, thus providing an arrangement wherein the size of the opening is gradually enlarged as the flow to the meter increases. ln other words, the position of the valve and diaphragm is directly proportional to the tlow rate through the meter. lt dirt should collect at the orifice when the valve is almost closed, to the extent that llow through the meter is stopped, the liquid will back up in the line and build up an increasing pressure head on the diaphragm. This increased head will open the valve and permit the dirt to be washed through. The diaphragm, as it moves in response to changing conditions in the solvent recovery line, also elccts operation ot the control mechanism and provides a ready means of accurately determining exactly what the condition in the meter or iiow line is at any given time while it is in use.

ln addition to the specific meter construction, and as previously indicated, an important object of the invention is to provide a combination in which the ilow sensing meter is utilized in coi.j notion with certain program control equipment to atleet the over-all operation of the maln one form or" the combination the recovery period of the machine is determined by and made directly responsive to the condition of the meter diaphragm during the recovery period. The machine will not proceed to thc completion of the total operating cycle until the meter indicates that recovery has, in fact, been completed to the standards required for safe operation. Since by the nature of the machine it is unlocked only at the end of the cycle, obviously this prevents access to the machine until the load is dry and the solvent has been removed. By tying the completion of the cycle to actual ending ol the recovery period, rather than to the termination of a preestablished sate time interval in which recovery theoretically should have been completed, average loads which require less than the sate time will result in cornpletion of the cycle in considerably less time than where the machine is on a straight time program. The difference represents time available for cleaning of the next load. For example, a 50% reduction of the recovery cycle will increase by 25% the number of loads that can be handled in a given operating day. This provides a great advantage to users as well as to owners of the machines. Of course, in addition to shortening the cycle time of the machine, the present invention will also increase the recovery time as necessary to completely dry the exceptional load of heavy clothing or retentit/e fabrics that would not be thoroughly dry in any straight time program.

ln another form of the combination the time program is interrupted once the solvent recovery systern has been set in operation, unless and until a preselected flow from the condenser has been sensed. lf the latter occurs, th program is again started. However, if solvent recovery docs not occur in normal fashion through some malfunction of the machine, the machine will not proceed on through the program, but will remain locked, thus again preventing access by the user to the interior oi the inachine and protecting him from exposure to dangerous fumes or Contact with the solvent itself.

These forms of the combination noted above can be combined in a single machine, and usually will be. The single pressure-sensing meter serves as the central element in the over-all combination and controls the response of the machine thereto.

@ther and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.

ln the accompanying drawir the specification and are to be read in conjunction "li with, and in which litre ieicrence numerals indicate parts in the various views;

FlG. l is a diagrammatic view showing a typical cleaning machine with which is connected a combined solvent meter and controller according to the invention;

FIG. 2 is a circuit diagram illustrating a typical time program controller and manner of connection of my meter therewith;

HG. 3 is an enlarged front elevational view or" the meter, parts being broken away for purposes of illustration;

FIG. is a side elevational View taken from the left hand side of RG. 3, parte again being broken away and shown in section for purposes oi illustration;

liG. 5 is a sectional View considerably enlarged taken along the line of PEG. l in the direction of the arrows; and

HG. 6 is an en iragrientary section teiten along line d d of Flo'. .n the direction of the arrows.

Referring now to the drawings and initially to FIG. l, reference numeral l@ indicates generally the basket or tumbler housing for a typical dry cleaning machine. The housing is provided with an access door ll having a solenoid actuated latch l2. The latch is normally closed, being opened upon energization oi the solenoid.

Solvent, for example perchlorethylene, is supplied to the basket housing by a puinp i3 through iilter i4 and lill line l5. The intake oi the pump is connected with a solvent storage tanlr lr6.

solvent recovery system for the machine embraces the blower i7 having drive motor lvl which forces a" through the leaters ld and into the housing. rPhe heated air as it passed through the housing serves to evaporate the solvent entrained in the load in the basket and carry it from the housing. The solvent-laden air is taken from the housing through duct il@ and lint trap and passed through the water cooled condenser 2li.

rihe solvent condensate which collects in condenser 2l is carried from the condenser through a water separator 22. and the separated solvent is delivered therefrom into the ilow line 23. Flow line 23 is connected with the input side oi the combined solvent meter and controller 24, the details of which will subsequently be described. lt suffices to note at this point that the liquid solvent ilows through element 24, passing therefrom through line 25 to the main solvent drain line 26 from the basket housing liti. The drain line 26 connects with the solvent storage tank le.

urning now to FlGS. 3 to 6 and to the details of construction of the element 2d, the main body comprises a circular iront member Z7 having a diametrically extending boss 27a formed on the front face thereof. The inner side oi member 27 is dished inwardly to provide a conical inside face 27h bordered by an annular hat surface 27C. he member 27 is provided centrally with a threaded opening 27d into which is screwed a fitting 23 having the orifice 2li.

ri`he fitting 2d is coupled by conventional coun means to the line earlier 1escribed The upper end oi boss 27a is bored longitudinally to provide a passageway Sil which merges with the conical inner race. A fitting 3l is threaded into passageway 3l?. This fitting is coupled through a conventional coupling with the flow line 2? from the condenser. Bhe opposite end of boss 27a is also drilled and tapped to provide a gravity drain passageway 32 into which is threaded a removable plug 33.

The conical inner tace Zb forms one wall of an enclosed chamber 3ft, the opposed wall of which is formed by a flexible impermeable diaphragm 35 preferably formed of rubber-like material. The margin of the diaphragm is secured between the annular surface 27C and a matching annular surtace provided on a bacli member 3d. Back member 36 is provided with an enlarged,

cyl-ii ical cavity Sb which is vented to the atmosphere by a vent 37. The back member 3d is secured to the member .27 by circunilerentially spaced bolts which entend through the `iront member, through registering epertures in the margin of the diaphragm, and into Ctei Vg tapped apertures (not shown) in the back member 3d. The front member is tightened securely against the margin of the diaphragm whereby to compressibly seal the joint against leakage.

Secured centrally to the diaphragm 35 and projecting through orifice is the needle valve member 39. The valve member 39 is of tapered construction and preferably is formed integral with a rod-like member d@ extending centrally through an opening in the diaphragm. The rod iii is secu ed to the diaphragm by the circular t which engage opposite sides oi the diaare conlined between a front flange i3 and .c nut 4d which is screwed onto the threaded rrion lea oi rod member and tightens rthe plates intermediate portion of the diaphragm FlG. 5, the rearward portion of rod receiver. in and supported by the axial bore "-g which is ereaded into a correspondcured, as by ner into or out of the back member.

valve member 39 is provided with a tapered conpos-.tion the valve member seats in and closes orice 29 to any li'ow therethrough. By virtue of the taper, it will be evident that as the valve member is backed out ot the orice the area open to flow through the orilice around the valve member will progressively increase.

the cross bar 47 is utilized to operably connect the valve rod with a snap-acting double pole single throw switch Switch is mounted on the back wall of r membe 3d by a mounting bracket Sti. rThe switch 4j has the actuating arm 5l which is resiliently biased t ward a position in which one ot the contacts normally is closed and the other is open, but normally the arm tire opposite condition. As best seen in FIGS. 4 and 5, cross bar i7 carries at that end adjacent the switch a threaded bolt 52 having a disk 53 secured to its inner end. Dislf. 53 is positioned to engage arm 52 and restrain it in ti e deflected position described above. Upon sufficient rearward movement ot the bar, the dislr permits switch arm to open the closed contact and close the open one. More will be said oi this later. The bolt 52 is threadedly received in a correspondingly threaded aperture in the cross bar to permit adjustment of the relationship between the dislf. and switch arm, while a lool: nut permits locking ine bolt in any desired adjustinent.

The other end oiC arm do carries an adjustable stop member which is in the iorm of a bolt which extends through a tapped aperture (not shown) in the cross bar. rhe stop member 55 is used to index the iost position of the valve member Obusly, it desired, by twisting bolt 55, the foremost position can be changed to one in which there is a slight opening through the orilice 29.

For protective purposes the switch 49 and associated operating mechanism, including the cross bar d?, is encased within a casing which is secured to back member Preferably the back member is rabbeted to provide annular shoulder 57 against which the casing seats. The casing can be secured to the back member by machine screws or bolts as at 58, which are received through the rim of the casing into suitably tapped apertures in the back member. The casing has mounted on its rearward end an electrical conduit fitting 59 through which extend the conductors for the switch 49.

The desired function of the switch `49 can best be understood by now referring to FIG. 2. In this figure, I have shown, to the extent believed necessary to understand my invention, a -typical time program controller for the cleaning machine. The controller includes the combined timer motor and speed reducer `@il which serves to drive a cam shaft 61. For purposes of illustration it will be assumed that the complete operating cycle of the machine is carried out within one revolution of shaft 6l. A plurality of cams o2, 63, 64, `65, 66, 67, 68, 69 are secured to shaft ol to turn therewith. The cams are shown in the position they assume at the start of the operating cycle of the machine. lt will further be assumed as understood that cams d2, 63, 64 control certain phases of operation leading up to the solvent recovery period, while cam o5 starts the blowers and other components of the solvent recovery system. I have not shown the details of the circuits involved nor the cam switches since they are conventional and are known to those skilled in this art.

Cam oe3 will be regarded as the cam which serves to shut or the solvent recovery system, while cam 69 triggers the door release circuit later to be described.

The cam 66 has the lobe 66a which serves to `engage and close the normally open Contact 7l)` when the lobe reaches the vertical position. This contact is located in a circuit which leads from main power conductor Ll through conductor 7l, normally closed contact 72a of relay 72, conductor 73, relay coil 74 and conductor 75 to line L2. Lines Ll, L2 are supplied from the alternating current power source for the machine. The coil of relay 72 is interposed in a circuit from L1 through conductor 76, switch and conductors 77 and 78 to L2. Switch 49 is shown in its normal position, which corresponds to the diaphragm and needle valve position illustrated in FIGS. 4 and 5. The lobe on cam `(6 is set to close contact 7@ a few minutes, say three to four, aiter the blowers have been started in response to cam 65.

As previously noted, and if the operation is proceeding normally, when recovery is started, solvent laden air is passed through condenser 21 and condensed solvent will begin to flow through the line 23 into the chamber 34 of the meter 2te. As solvent collects in the chamber the p cssure in the chamber will build up until it is sufficient to overcome the spring loading on the diaphragm, at which time the needle valve 39 will be backed out of oriiice until a balance of pressure exists. This in turn causes rod to shift lengthwise, carrying -with it the cross bar d'7. When the valve is open to the point where the desired minimum tlow rate during recovery has been reached, rod il causes the movable contact Lilia of switch i9 to close the circuit between conductors '7n and 77. This is the broken line position for switch contact 49, as illustrated in FIG. 2. The required pressure in chamber 352 to cause this is preselected on the basis of the over-all characteristics of the machine, including desired minimum rate of solvent recovery.

lf at the time that lug een closes Contact 'itl the diaphragm has not shifted contact 4% to the broken line position, the timer motor will be deenergized and will remain decnergized until ilow is sufficiently great to cause contact 49a to move to the broken line position. If contact 72a remains closed, which it does until contact 49a moves to the broken line position, then upon closing of contact 76 relay 7d is energized, opening its normally closed contact 74o. This latter contact is in series with timer motor M, and consequently the timer motor is deenergized.

The timer motor remains deenergized until the flow reaches the rate suiiicient to shift contact @a to the broken line position. When this occurs, relay 72 is cnergized, opening contract '72a and deenergizing relay 74. Thus, the motor o@ is again energized and cam lobe een will move out from engagement with contact 7l), permit ting it to open.

Obviously, if the desired recovery rate has een reached at the time that cam contact 7? is closed, then the timer will continue on through the closing and reopening of Contact 70. The circuit to relay 74 is broken due to the euergization of relay 72 'at the time of shifting of Contact 49a to the broken line position.

ln either event, it will be evident that the time for the machine will stop until and unless a desired ilow rate is reached. lf it is never reached, due to malfunction of the machine or any other cause, the cycle of the machine will never be completed. Since completion of the cycle is necessary to unlock the machine, the customer is prevented access to the machine at a time when, because of lack of recovery, dangerous quantities of solvent remain therein.

Assuming, however, that recovery is normal and operation of the timer is resumed, the lobe 67a will now approach and close its associated contact 79. The lobe 67a is so located relative to lobe 66a that only a short interval, say two minutes, exists following the opening of contact 7@ and the closing of Contact 79. The meter controlled contact 49a will still be in the broken lines position. Therefore, closing of contact 79 energ-izes a second relay Sti, having a contact `Stia in series with timer motor o9 again stopping the timer. Relay 8d is in a circuit from line L1 through conductors 8l, 32, normally closed relay contact 83a and conductor S4 to line LZ.

The timer will remain stopped until the meter controlled Contact 49a returns to the normal position which corresponds to a llow approximately zero through the meter.

When contact 49a returns to its normal position, which is the solid line position of FIG. 2, relay 83 is energized, opening contact 33a and breaking the circuit to relay Sti. This results in reclosing of the circuit to the timer Amotor titl, permitting it to continue the rotation of the shaft 6l. Cam e8 will thereafter shut or? the recovery system and cam 69 trigger the door release circuit through closing the Contact 35 to energize door latch solenoid Obviously, such additional cams or circuits as needed will be provided to reset the machine and provide for starting of the cycle. These, however, play no part in my invention, and further detail is believed unnecessary.

From the foregoing it will be evident that l have provided an arrangement wherein the length of the solvent recovery period and the progress of the machine through its cycle is made dependent on the occurrence of certain desired conditions in the solvent recovery system. lf none, or an insuilicient amount of condensed solvent is delivered to the meter as to trip switch e9, then the machine will remain locked against access. Thus. the unit produces a safety lock in the event of any malfunctions, including power failure, cooling water failure, circulating fan failure, heater failure, basket dry belt failure, stoppage of air circulation for any reason, and failure to condense and drain solvent in the recovery system for any reason. While each of these failures can be detected by other devices, such as centrifugal switches, pressure switches, thermal elements, dilferential pressure switches and the like, in my invent-ion all of these can be replaced by the combination herein set forth.

The meter and controller design, in and of itself, has many advantages also. Since the meter receives all the solvent from the condenser there is no need for a bypass sample system. rl`he orice 29 can be made of relatively large diameter, say 1/15 inch, which is large enough to pass any normal sediment that may be in the solvent. If sediment should collect at the orifice when the valve almost closed, it will, of course, shut off liow. However,

and permit the sediment to be washed through. )In other words, the meter is self-cleaning if sufficient sediment is collected to cause plugging of the meter.

ln the unlikely event that dirt particles larger than 3/16 inch are present in the solvent, which would jam the orifice even when the valve is fully open, the unit can be cleaned by simply removing the fitting 28. The iit'ting is removable without taking the unit from the machine and it will not alect the calibration thereof.

lt will also be evident that through the combination set forth the system is such that it is fail safe. lf prior to the start of recovery the diaphragm should rupture, the meter would never indicate that recovery had been established and the machine would stay loci/:ed just as under the conditions where insufficient solvent is delivered to the unit to trip switch 49 and restart the timer mechanism. By the same tol-zen, if during recovery the oriiice is unable to clean itself when plugged, the diaphragm will fail to return to the normal position because of the pressure of solvent contained within chamber 3d and the unit would never indicate, through switch 49, that recovery had been completed. Therefore, the machine will remain locked.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth together with other advantages which are obvious land which are inherent to the structure.

lt will be understood that certain features and subcombinations are of utility and may be employed Without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention lwithout departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. In a cleaning machine having a housing wherein 'solvent is contacted -vvith work to be cleaned, a solvent recovery system including a condenser and means for withdrawing solvent vapor from said housing during the solvent recovery period and passing it to said condenser, and program means operable to establish the sequence of operation of said machine and to put it into the recovery eriod, the combination therewith of a solvent flow line connected )with said condenser to carry condensed solvent therefrom, a solvent meter interposed in said line and including pressure sensitive means normally substantially closing the meter to ilow of liquid therethrough but operable in response to the presence of liquid solvent in the meter to open a tlow path through the meter, and means `operably connected with and actuated in response to said pressure sensitive means to control the effectiveness of :said program means.

2. The combination as in claim l, said last named Vmeans operable to deactivate said program control means following the start of the recovery period if the solvent vpressure in the meter is less than a predetermined value.

3. The combination as in claim l, said `last named means operable to end the recovery period in response to a preselected minimum pressure in the meter.

4. ln a cleaning machine having a housing wherein solvent is contacted with work `to be cleaned, a solvent recovery system including a condenser and means for withdrawing solvent vapor from said housing during the solvent recovery period and passing it to said condenser, and an electrically powered program controller operating to initiate the recovery period and control the operation of the machine following recovery, the combination therewith of a solvent ow line connected .with said condenser to carry condensed solvent therefrom, la solvent meter interposed in said line and including pressure sensitive means normally substantially closing the meter to flow of liquid therethrough but operable in response to the presence of liquid solvent in :the meter to open a ilow path through the meter, and means operably connected with and actuated in response to said pressure sensitive means to deenergize said program controller following the initiation of said recovery cycle if the liquid pressure in said meter is less than a preselected value and to maintain said prog-ram controller deenergized until said selected pressure is reached.

5. in a cleaning machine having -a housing wherein solvent is contacted with work to be cleaned, a solvent recovery system including a condenser and means for withdnawing solvent vapor from said housing during the solvent recovery period and passing it to said condenser, and an electrically powered program controller operating to initiate the recovery period and control the operations of the machine following recovery, the combination therewith of a solvent ilow line connected with said condenser to carry condensed solvent therefrom, a solvent meter interposed in said line land including pressure sensitive means normally substantially closing the meter to flow of 'liquid therethrough but operable in response to the presence of liquid solvent in the meter Kto open la ilovv path through the meter, and means operably connected with and actuated in response to said pressure sensitive means to prevent the operations of the program contro-ller subsequent -to the recovery period until the pressure in said meter has dropped to a preselected minimum.

6. in a cleaning machine having a housing wherein solvent is contacted with work to be cleaned, an access door to said housing, releasable lock means normally locking said door closed during operation of the machine, a solvent recovery system including a condenser and means for withdrawing solvent vapor from said housing during the solvent recovery period and passing it to said condenser, land program means operable to establish the sequence of operation of the machine, including initiation of said recovery period and release of said locking means, the combination therewith of a solvent llow line connected with said condenser to carry condensed solvent therefrom, a solvent meter interposed in said line `and including pressure sensitive means normally substantially closing the meter to ow of solvent therethrough but operable in response to presence of solvent to open a llow path for said solvent to the meter, and means operably connected with and actuated in response to said pressure sensitive means to condition said program means to prevent the release of said locking means until the pressure in said meter has reached a predetermined minimum value.

7. The combination as in claim 6 including means operably connected with and actuated responsive to said pressure sensitive means to deactivate said program means following the initiation of the recovery period until the liquid pressure in the meter reaches a preselected value.

8. For use in a cleaning machine having a solvent recovcry system including a condenser fitted with a liquid recovery line from the condenser, a solvent meter adapted to be connected with said recovery line and having a chamber therein for receiving liquid from said line, one wall of said chamber comprising a liexible diaphragm, the chamber wall opposed from said diaphragm being provided with an oriiice for outlet of liquid, a tapered needle valve member connected with said diaphragm `and extending into said orifice, said valve member movable longitudinally in said orice in response to movement of said diaphragm to vary the cross-sectional flow area of said orilice whereby to provide a means orp establishing a balanced llow rate to and from said chamber, control opensting means connected with and actuated in response to movement of said diaphragm, and control means operably associated with said control operating means and having a rst and second condition, said operating means acting to effect a shift from :one of said conditions to the other at a preselected flow rate.

9. A solvent meter as in claim 8 wherein said control means includes a switch, and said operating means include switch `trigger means connected with said diaphragm and operated responsive to movement of said diaphragm to actuiate said switch.

References Cited in the 1e of this patent UNITED STATES PATENTS 1,783,646 Hajek Dec. 2, 1930 io Edlich Nov. 5, 1935 Hetzer July 18, 1939 Heft et a1 Oct.'4, 1960 Smith Oc. 3, 1961 Rand Aug, 21, 1962 FOREGN PATENTS Switzerland Feb. 16, 1939 

1. IN A CLEANING MACHINE HAVING A HOUSING WHEREIN SOLVENT IS CONTACTED WITH WORK TO BE CLEANED, A SOLVENT RECOVERY SYSTEM INCLUDNG A CONDENSER AND MEANS FOR WITHDRAWING SOLVENT VAPOR FROM SAID HOUSING DURING THE SOLVENT RECOVERY PERIOD AND PASSING IT TO SAID CONDENSER, AND PROGRAM MEANS OPERABLE TO ESTABLISH THE SEQUENCE OF OPERATION OF SAID MACHINE AND TO PUT IT INTO THE RECOVERY PERIOD, THE COMBINATION THEREWITH OF A SOLVENT FLOW INE CONNECTED WITH SAID CONDENSER TO CARRY CONDENSED SOLVENT THERFROM, A SOLVENT METER INTERPOSED IN SAID LINE AND INCLUDING PRESSURE SENSITIVE MEANS NORMALLY SUBSTANTIALLY CLOSING THE METER TO FLOW OF LIQUID THERETHROUGH BUT OPERABLE IN RESPONSE TO THE PRESENCE OF LIQUID SOLVENT IN THE METER TO OPEN A FLOW PATH THROUGH THE METER, AND MEANS OPERABLY CONNECTED WITH AND ACTUATED IN RESPONSE TO SAID PRESSURE SENSITIVE MEANS TO CONTROL THE EFFECTIVENESS OF SAID PROGRAM MEANS. 